Individuals diagnosed with the disease may also experience sleep disorders, morning stiffness, poor concentration, and occasionally mild-to-severe mental symptoms such as anxiety or depression.

There is no cure, and no treatment will address all of the symptoms, but some symptoms may be alleviated by physical therapy, cognitive behavioral therapy, temporary drug therapy (such as amitriptyline, duloxetine, or pregabaline) and multimodal therapies.

Researchers hypothesized that vitamin D supplementation would reduce the degree of chronic pain experienced by FMS patients with low levels of calcifediol and also might improve other symptoms.

"Low blood levels of calcifediol are especially common in patients with severe pain and fibromyalgia. But although the role of calcifediol in the perception of chronic pain is a widely discussed subject, we lack clear evidence of the role of vitamin D supplementation in fibromyalgia patients," lead investigator Florian Wepner, MD, of the Department of Orthopaedic Pain Management, Spine Unit, Orthopaedic Hospital, Speising, Vienna, Austria, said.

"We therefore set out to determine whether raising the calcifediol levels in these patients would alleviate pain and cause a general improvement in concomitant disorders," the researcher said.

In a randomized controlled trial, 30 women with FMS with low serum calcifediol levels (below 32ng/ml) were randomized to a treatment or control group.

It was found that the treatment group improved significantly on a scale of physical role functioning, while the placebo group remained unchanged. The treatment group also scored significantly better on a Fibromalgia Impact Questionnaire (FIQ) on the question of "morning fatigue." However, there were no significant alterations in depression or anxiety symptoms.